1. Field of the Invention
The invention concerns a device for operating an articulated boom, more particularly a concrete placement boom, linked to a boom block, which articulated boom includes at least two boom arms which are respectively limitedly pivotable relative to the boom block or relative to an adjacent boom arm about respective horizontal articulation axes, which articulation axes are parallel to each other, by means of a preferably hydraulic operated drive unit, via a preferably remote control device including a position controller for movement of the boom with the aid of the individual actuating elements associated with the individual drive units, and with sensors associated with the individual boom arms, articulation axes and/or drive axes for the path or angle measurement for position control. The invention further concerns a large manipulator, in particular for concrete pumps, with an articulated boom linked to the boom block and with a device for operating thereof of the type described above.
2. Description of the Related Art
Mobile concrete pumps are conventionally operated by an operator, who is responsible not only for the control of the pump but also for the positioning of the distribution hose which is provided at the tip of the articulated boom. The operator must control multiple rotational degrees of freedom of the articulated boom via the associated drive units with movement of the articulated boom in non-structured three dimensional work space with due consideration of the boundary conditions existing at the construction site. In order to simplify the manipulation or operation in this respect, and operating device has already been proposed (DE-A-430627) in which the redundant articulated axes of the articulated boom are controllable collectively with one single control manipulation of the remote control device in any rotational position of the boom base, independent of the rotation axis thereof. Therein the articulation boom carries out an extension and retraction movement which can be observed by the operator, wherein in addition the elevation or height of the boom tip can be maintained constant. In order to make this possible, the control device includes a remote control device controllable, computer supported coordinate transformer for the drive units, via which the drive units of the articulated boom are actuated in the one main adjustment direction of the remote control device independently of the drive unit for the rotation of the boom base with accomplishment of an extension or retraction movement of the articulated boom while maintaining a predetermined height of the boom tip. In a different main adjustment direction of the remote control device the drive unit or drive unit of the rotation axis of the boom base is operable independent of the drive units of the articulated axis with carrying out a rotation movement of the articulated boom, while in a third main adjustment direction the drive units of the articulated axis are operable independently of the drive units of the rotation axis while carrying out a raising and lowering movement of the boom tip. A basic precondition for such an operation of the articulated boom is a position controller which includes among other things a sensor or sensor logic for the path or angle measurement associated with the individual boom arms, articulation axes and/or drive units. Since faults in technical systems of this type, which include not only mechanical but also electronic and hydraulic components, cannot be completely avoided, there is a need for a safety monitoring system which warns the user and when necessary takes action for safety purposes. Therein it is necessary, to recognize and evaluate the occurring problems by sensing with the objective to overcome the faults at least temporarily and to prevent undesired faulty operations and damage. A turning off of the boom and pump functions has until now been possible using an emergency turnoff switch, which is operated by the user.